1. Field of the Invention
The present invention relates to a data communication apparatus, which is applied to e.g. MFP (Multi Function Peripherals), a multi functional digital copying machine, that is able to establishing a session with a client by a call control protocol and performing data communication by a data communication protocol after the session is established, a data communication method, and a data communication processing program stored on a computer readable medium to make a computer for a data communication apparatus execute data communication processing.
2. Description of the Related Art
The following description sets forth the inventor's knowledge of related art and problems therein and should not be construed as an admission of knowledge in the prior art.
For recent years, along with the popularization of Internet, technologies which enable access via the IP (Internet Protocol) network from a client such as a personal computer to a data communication apparatus such as MFP, and transmission of data such as image data, have become in widespread use.
As one of the conventional methods of the data communication via the IP network as mentioned above, an art is heretofore known already (for example, Japanese Unexamined Laid-open Patent Publication No. 2005-159588): establishing a session by SIP (Session Initiation Protocol) that is a call control protocol, and transferring data by a data communication protocol other than the call control protocol after the session is established.
Another art is also heretofore known already (Japanese Unexamined Laid-open Patent Publication No. 2005-86580): controlling to permit/reject data reception according to preliminarily registered network addresses (an available network range) and IP addresses.
However, the former heretofore known art mentioned above is not designed so that a client, which established a session by SIP can perform data communication preferentially, thus, data may happen to be received also from other clients while and after the session is established by said client. In other words, data from a client, which already established a session, cannot be received efficiently.
Besides, the latter heretofore known art mentioned above is not specially designed either for session establishment or for data communication, thus the clients other than those whose IP addresses are preliminarily registered don't have a chance to transfer data at any time. Thus, it is so inconvenient that the art cannot be applied to a call control by SIP in its entirety.
The description herein of advantages and disadvantages of various features, embodiments, methods, and apparatus disclosed in other publications is in no way intended to limit the present invention. Indeed, certain features of the invention may be capable of overcoming certain disadvantages, while still retaining some or all of the features, embodiments, methods, and apparatus disclosed therein.